I love a good mystery.
Personally, I agree there is a flowerpot inlay, and the tailpiece is IS either a byrdland tailpiece or one that is exactly like it that might say something else (although I would say that is so out there it is not likely).
Also, while I can't be sure the top is spruce, it sure looks like spruce more than maple (laminated or not). For one, I see what I think is a slightly different color than the sides. And also, the biggest clue is the changes it shows to different angles to the lighting. At different angles, more or less of the straight grain shows, as well as contrast between the left and right sides. Spruce looks like this. Maple usually shows more or less flame and color perpendicular at different angles.
I am with L5LARRY that the body is deeper than the standard Byrdland or 350T. It does not look like a 350/L5 full depth, but it does look like the in between 125/135 depth.
So, if that is correct, we have TWO major differences: the body depth and the fret markers. SO, THAT is the biggest clues, right?
In my opinion, if we look at what Gibson has done in the past as far as variations and different models, it is not unbelievable that Gibson would make something with different specs while not introducing a new model. When Gibson has introduced new models, especially with arch-top electrics, they usually define them with different tailpieces and headstock inlays.
IMO, and my best guess from what I can see, is that this guitar is a VARIATION and a rare version of a Byrdland, and Gibson has made it to be a Byrdland.